Question

a man covers a distance of 24km in 3 and half hrs partly on foot at the speed of 4.5 km pr hr and partly on bicycle at the speed 10 km pr hr .. find distance covered on foot..

Answer 1

Let the distance traveled by foot be x
Then distance traveled on bicycle = 24 - x
(since total distance = 24 km)

Now time = distance/speed

By Foot -->
Distance = x km
Speed = 4.5 km/hr
Time = x/4.5

By Bicycle -->
Distance = 24 - x
Speed = 10 km/hr
Time = (24 - x)/10

Total time = 3.5 hours

Time taken by foot + time taken by bicycle = total time
x/4.5 + (24 -x)/10 = 3.5

To simplify the equation, multiply it by 90,
90 x( x/4.5 )+ 90 x (24 - x)/10 = 90 x 3.5
20x + 9(24 - x) = 315
20x + 216 - 9x = 315
11x = 315 - 216
11x =  99
x = 9 m

So, he traveled 9 km by foot and (24- 9 ) = 15 km by bicycle
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